Haden, Prince of the Underrealm, is determined to defy his fate to protect Daphne, even as they and their small group of friends continue the search for the lost Kronolithe, the key of Hades--but his undeclared love for a mortal girl is a terrible risk, and they must both decide what they are willing to sacrifice to protect one another.

As monsters walk the streets of San Francisco, unseen by humans, three teenaged descendants of Medusa, the once-beautiful gorgon maligned in Greek mythology, must reunite and embrace their fates.

Triplets Gretchen, Grace, and Greer, descendants of Medusa, continue to battle the monsters who walk the streets of San Francisco, unseen by humans, but realize they must enter the abyss if they are to protect their loved ones and their world.

Nico, the son of Hades, and his boyfriend Will, the son of Apollo, travel to Tartarus, the deepest, darkest part of the Underworld as they attempt to rescue an old friend.